Replacing same rows with same variables in first to third column
2 views (last 30 days)
Show older comments
Hi. I have two matrices named aa and m.
aa=[1 2 3 7
4 5 6 8
7 8 9 9
3 2 3 8
6 5 6 7
7 8 7 9];
mm=[1 2 3 5
4 5 6 9
7 8 9 6];
I want to replace the rows of aa with the rows of m that have the same values in first to third column.
How can I do that?
Thanks a lot.
2 Comments
Image Analyst
on 21 Dec 2017
What if m is
mm=[1 2 3 5
1 2 3 9
4 5 6 9
7 8 9 6];
Which row of m, the first or the second, should replace the first row of aa?
Answers (2)
Jos (10584)
on 21 Dec 2017
No need for loops at all! Use both outputs of ismember and replace accordingly
aa = [1 2 3 7
4 5 6 8
7 8 9 9
3 2 3 8
6 5 6 7
7 8 7 9
1 2 3 999];
mm = [1 2 3 5
4 5 6 9
7 8 9 6];
[tf,loc] = ismember(aa(:,1:3),mm(:,1:3),'rows')
% tf indicates which rows in aa are found where (loc) in mm (only for columns 1-3)
aa(tf,:) = mm(loc(tf),:) % replace those rows
See Also
Categories
Find more on Matrices and Arrays in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!